JPS5921258B2 - die casting injection sleeve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an injection sleeve installed in a die casting machine.

In general, this type of injection sleeve is used as a conduit through which the molten metal to be cast is poured and is injected into the mold surface at high speed and high pressure by the movement of the plunger tip, so it is heat resistant and wear resistant. However, in the case of lead Zn, magnesium Mg1 aluminum AI alloys, etc., where the temperature of the molten metal, that is, the melting point of the metal to be cast, is 700°C or less, JIS standard 5K is required.
Although the above characteristics can be met by using an injection sleeve made of hot work tool steel such as D-61, recently 10
When die-casting high-melting point alloys such as cast iron and cast steel that exceed 00℃, injection sleeves that can handle high-temperature metal melting are made of surface-treated refractory metals such as molybdenum Mo alloys and tungsten W alloys. However, it has the problem that its service life is shortened due to early deterioration.

That is, the following conditions are required for the injection sleeve in die casting of high melting point metal.

a) For high melting point metal materials such as cast iron, ordinary cast steel, and stainless steel cast steel, a maximum molten metal temperature of 1600°C is sufficient, so the injection sleeve must be made of a material with a melting point of 1600°C or higher.b) C) Has excellent heat resistance (molten metal) and does not cause chemical reactions with high-temperature molten metal; C) Has high abrasion resistance and durability at high temperatures; d) Can withstand repeated thermal cycles that rapidly change from high to low temperatures. e) It is rich in strength and toughness at high temperatures, has good processability as an injection sleeve, and is inexpensive.

However, the current situation is that conventional injection sleeves manufactured from a single material do not satisfy the above-mentioned conditions.

In view of the above-mentioned conditions, the present invention includes disposing a large number of heat-resistant and wear-resistant ring members made of ceramic or the like at equal intervals on the inner circumferential surface of the injection hole through which the plunger tip is inserted. An object of the present invention is to provide a die-cast injection sleeve that satisfies the above conditions by forming an injection sleeve by casting a heat-resistant metal so that the ring member and the heat-resistant metal are alternately exposed on the inner peripheral surface. That is.

Hereinafter, in FIG. 1, which will be described in detail with reference to the illustrated embodiment embodying the present invention, an injection sleeve 1 is shown in its steel outer cylinder 1.
One side (the left side in the figure) of the injection hole 2 of a is aligned with the pouring hole of the mold M and is attached to the mold M, and the other side of the injection hole 2 (the right side in the figure) is appropriately driven. A plunger tip T reciprocated by means is closely inserted.

Furthermore, an injection port 3 for molten metal, which is communicated with the injection hole 2, is provided through the plunger tip T side of the injection sleeve.

An injection port 3 is provided on the inner peripheral surface of the injection hole 2 of the injection sleeve 1.
From the pouring spout of the mold M, there are a large number of glue members 4~
4 are arranged at equal intervals and are cast together with a heat-resistant metal layer 5 made of a material such as heat-resistant cast steel or heat-resistant superalloy, which has high strength under high temperatures, during molding.

Therefore, the inner peripheral surface of the injection hole 2, the inner surfaces of the ring members 4 to 4 and the inner surface of the heat-resistant metal layer 5 are alternately exposed.

This ring member 4 is sintered from a ceramic material with high heat resistance, wear resistance, etc., such as silicon carbide (carborundum) S iC system, trisilicon trisilicon 5i2N4 system, and aluminum oxide Al 20'3 system. Alternatively, the ring member 4 is formed into the shape shown in FIG. 2 by means such as hot pressing, and the width d2 of the ring member 4 is thinned to prevent local concentrated stress from acting as shown in FIG. It is set to the dimension '/2dl≦d2≦2d1 with respect to the thickness d1. For example, if the width d2 is set to a size closer than twice the wall thickness d1, the injection sleeve 1 may be During the manufacturing process, when the ring member 4 is cast together with the heat-resistant metal layer 5, cracks may occur in the ring member 4 itself due to solidification shrinkage. Local density non-uniformity often occurs, and furthermore, the width d2 is l/of the wall thickness d1.
Even if the size is set to be smaller than 2, the degree of cracking will increase similarly to the above, which is undesirable.

In addition, in order to improve the bonding state with the heat-resistant metal tube 5, a layer of nickel Ni, iron F"e, etc. is applied to the surface of the ring member 40, for example, with a thickness of about 5 to 100 μm by means of electroless plating or plasma coating. It has been coated with.

Further, the ring member 4 is cast into the heat-resistant metal layer 5 by a commonly used precision casting method using a vanishing model.

The injection sleeve 1 of this embodiment is constructed as described above, and without explaining an example of the manufacturing procedure below, the ring members 4 to 4 are formed by hot pressing to have a density of 32 and a bending strength of 120 kg/ As shown in Fig. 2 for the β-type Si3N4 molded body of No.
Molded into a shape with a width d2 of 8Wtm and an inner diameter of 60mmφ,
The surfaces of the ring members 4 to 40 are coated with iron (Fe) to a thickness of approximately 30 μm by plasma coating means.

Next, about 30 ring members 4 to 4 are placed in series at intervals of 3 ff1771 in a mold for a vanishing model and fixed by a desired means, and then a vanishing model mainly made of urea resin is formed. The mixed powder is melted and poured into the mold to form a vanishing model.

Then, a slurry of ethyl silicate and zircon powder was applied to the model, and molten silicon dioxide was sprinkled on the model. This was repeated several times to form a ceramic mold with a thickness of approximately 7 Bmm. After drying, The model is demolded to form a ceramic mold containing ring members 4 to 4, and this mold is placed in a reducing gas atmosphere at about 1000° C. for 4 hours, for example, to prevent oxidation of the coating metal of the ring members 4 to 4. Preheat at .

Subsequently, this preheated mold is heated to approximately 10-3 to 10'
Installed in a vacuum melting and casting furnace of about torr, and ROM C
The ring members 4 to 4 are cast by pouring the molten material to form the heat-resistant metal layer 5 made of a nickel-Ni base alloy containing r about 12%, molybdenum Mo at 4%, and other trace elements. Metal layer 5, i.e. ring member 4 on the inner surface
A sleeve is cast in which the heat-resistant metal layer 5 and the heat-resistant metal layer 5 are alternately exposed.

Thereafter, the inner surface of this sleeve is finished polished and shrink-fitted into a steel outer cylinder 1a having an outer diameter of 80 mm and an inner diameter of 70 mm, for example, with an interference of about 20 μm, thereby producing the injection sleeve 1 shown in FIG. It is something to do.

In addition, as another manufacturing procedure, the ring members 4 to 4 are molded as an SIC molded body by sintering means, coated with nickel Ni by electroless plating means, and a ceramic mold is molded in the same manner as in the previous step. Previous I
A sleeve is formed by casting the ring members 4 to 4 with a molten material to form a heat-resistant metal layer 5 made of a chromium-Cr-based alloy containing 20% iron and other trace elements under the same conditions as described above. However, the injection sleeve can also be manufactured by processing in the same manner as described above.

Next, another example of the injection sleeve 1 will be explained with reference to FIG. This heat-resistant metal layer 5' is used as it is as the steel outer cylinder 1a in the previous embodiment, and the other structures and manufacturing procedures are the same as in the previous embodiment, so their explanation will be omitted.

In the above-mentioned manufacturing procedure, the ring members 4 to 4 are arranged at intervals of about 3 holes, but this interval allows the molten material to form the heat-resistant metal layer 5 to easily flow in during casting, and the ring members 4 to 4 It is desirable to set at least 1 to 3 questions so that the ring members 4 to 3 can be combined.
The sleeve composed of the heat-resistant metal layer 4 and the heat-resistant metal layer 5 may be subjected to surface treatment if necessary.

As described above, in the present invention, a large number of heat-resistant and wear-resistant ring members made of ceramic material or the like are arranged at equal intervals on the inner peripheral surface of the injection sleeve, and the ring members are made of heat-resistant metal. Since the ring member and the heat-resistant metal layer are cast in a metal layer and are alternately exposed on the inner circumferential surface, the inner circumferential surface of the injection sleeve is made of a material such as a ceramic material forming the ring member. Not only does it have excellent heat resistance (molten metal resistance) and abrasion resistance at high temperatures due to its characteristics, but the alternating exposure of the ring member and the heat-resistant metal layer eliminates brittleness, which is a disadvantage of the material of the ring member. It is possible to eliminate the thermal shock force at each part and minimize the deformation due to thermal stress, and the width of the ring member is larger than about half the wall thickness dimension and smaller than about twice the wall thickness dimension. By setting this, it is possible to eliminate cracks during casting as much as possible and achieve good casting, thus satisfying the various conditions for an injection sleeve that is fully compatible with die casting of high melting point metal materials. It has the advantage of improving its durability and reliability.

[Brief explanation of the drawing]

The figures show embodiments of the present invention, in which Fig. 1 is a sectional view showing the entire injection sleeve, Fig. 2 is a perspective view showing the ring member, and Fig. 3 is a sectional view showing the entire injection sleeve.
The figure is a sectional view showing another example of the injection sleeve. 1...Injection sleeve, 4...Ring member, 5...Heat-resistant metal layer.

Claims (1)

[Claims] 1. A large number of heat-resistant and wear-resistant ring members made of ceramic or the like are arranged at equal intervals on the inner peripheral surface from the injection hole of the injection hole through which the plunger tip is inserted to the pouring hole of the mold. The ring member is cast in a heat-resistant metal so that the ring member and the heat-resistant metal layer are alternately exposed on the inner circumferential surface, and the ring member has a width larger than about half of the wall thickness and a heat-resistant metal layer. A die-cast injection sleeve characterized by being set smaller than about twice the size.